why does it hesitate at 60mph?

I have a 2001 GA SE and it seems that when I am on the highway going between 60-70mph it starts to hesitate like it's slightly losing power. When I rev it and play with it, it moves on fine.

I replace my cat and that helped majorly. I am wondering if it's a faulty spark plug or what. Advice would be helpful , thanks

Gabe

Same problem with my 93, i had to replace the spark plug wires... I was told if theres hesitation in lower speeds, its the plugs.. if its higher speeds, its the wires... But, your car isn't that old where the wires would be bad, but i guess you never know

thanks I'm gonna tune it up and see what happens

sounds like my problem with my 96 pontiac grand am. the engine shutters from 45-60 MPH if i rev it up it stops i have changed spark plugs and cables not fixing it

Just to give you and update. YOu must have been searching because that post was kinda old. Anyhow I took my car in to a muffler shap and had the catalytic converter replaced. that solved the problem.